Plastic compositions



Patented Feb. 14, 1939 amass rmsno oomosmons Courtney Oonover, St.

Louis, Mo., assisnor to Monsanto Chemical Company, St. Louis, Mo., acorporation of Delaware No Drawing.

Application April 27.- 1935, serial I No. 18,536. In Great Britain April10, 1935 19 Claims.

The present invention relates to compounds suitable for use asplasticizers and modifiers of artificial and natural resin-likematerials.

The application is a continuation in part of co-pending applicationSerial Number 643,534, filed November 19, 1932, which issued as PatentNo. 1,999,181.

The main objects of the invention are to vide:

A class of plasticizers of the above described compositions which arerelatively inexpensive to prepare; which are of unusually high boilingpoints and exhibit an exceptionally high degree of permanency in plasticcompositions; which are non-odorous; which are readily compatible withnitrocellulose and such like materials, and are relatively light stabletherein; which are plasticizers of nitrocellulose and other plastics atrela- PIO- tively low temperatures; and to novel methods of preparingthe above described compositions.

As is well known, most of the commonplastic materials, such as celluloseesters, and such natural and artificial resins as shellac, alkyd resins,phenol-formaldehyde resins, styrol resins and vinyl resins, prepared bycondensing such vinyl compounds as vinyl acetate, vinyl chloride,mixtures thereof or modified vinyl resins obtained by further condensingthe above described vinyl products with an aldehyde, such asformaldehyde, acetaldehyde or furfuraldehyde, tend upon exposure tobecome hard and brittle. As a result,

articles molded therefrom or films formed from solutions thereof, withina relatively short period of time tend to crack and check. In order toreduce this tendency, it is customary to incorporate into the materialscertain modifiers termed plusticizers which have the property ofincreasing the elasticity and flexibility of the compositions withoutrendering the latter unduly soft.

Although many compounds have been suggested as acting as softeners forthese compositions, but relatively few of them are of commercial valueand even of those which are employed in commercial practice still fewerare free from various objectionable features. Some of them are of toolow a, degree of compatibility with the resins which are to beplasticized to admit of their use in adequate quantities. Others, eventhough they are relatively compatible with the resins, are so volatilein their nature that they soon evaporate and leave the materialscontaining themunpla's ticized. Some, while they function satisfactorilyat normal temperatures, upon exposure to relativelylow temperaturesbecome hard and brittle and as a result they are unsuitable for usewhere they are exposed to excessive cold. Another common defectencountered consists in the tendency of the materials to becomediscolored upon exposure to light and air.

The present invention involves the discovery that the non-resiniferousesters of 2,2. or 2,4 benzophenone dicarboxylic acid constitute valuableplasticizers and modifiers of cellulose esters and artificial andnatural resins.

The neutral esters of benzophenone 2,2 dicarboxylic acid are especiallyimportant members of this class. These may be represented by theformula:

001: oon, I

compound is replaced by the carboxy group of the acid.

The above described esters, it will be observed, consist of the simplemonomeric products. Complex resinous polymeric products obtained byprolonged heating of the keto dicarboxylic acid in the presence of apolyhydroxy alcohol are not contemplated, and are not suited for thepurposes of the present invention.

Compounds suitable for the purpose are'obtained. by esterification ofbenzophenone 2,2 dicarboxylic acid. The preparation of the lactone ofthis acid by decarboxylation of phthalic anhydride under substantiallyanhydrous conditions is described in detail in the above notedapplication Serial Number 643,534 of November 19, 1932, which issued asPatent No. 1,999,181.

The esteriflcation may be accomplished by various methods. Oneconvenient method involves the treatment of the lactone of benzophenone2,2 dicarboxylic acid with an alkali (inslight excess) such as sodiumhydroxide or cal-.

cium hydroxide. The sodium hydroxide is employed hot and preferably of aconcentration ranging from 10 to 20 per cent, although it will beappreciated that somewhat higher or even lower values may be employed ifdesired. The sodium salt of-the acid thus obtained is then 4 neutralizedwith a slight excess of such mineral acid as dilute sulfuric orhydrochloric acid to.

acid, such as'sulfurlcacid or hydrochloric acid.

several hours (for instance, 5 hours) until esterification is completeand water of reaction is no longer formed. It is to be understood thatduring this period of refluxing the water of reaction is withdrawn fromthe system by wellknown methods. It may be desirable to add smallquantities of fresh alcohol from time to time in order to maintain theconcentration thereof throughout the period of reaction. The cessationof the formation of water is one criterion of the completion of thereaction; however, other criteria may be employed if desired. Oneconvenient test is a titration test of a sample of the reaction productto ascertain when substantial neutrality is reached.

Purification may be eifected by evaporating excess-alcohol and ifdesired the product may be decolorized by treatment with charcoal or byoxidation with permanganate of potash. These two treatments may becombined if so desired. These steps are, of course, conventional andneed not be described indetail.

The butyl ester of benzophenone 2,2 dicarboxylic acid is a heavy, oily,non-odorous liquid, boiling at a temperature of 228 C... at a pressureof 1.8 mm. (absolute). This ester is compatible with nitrocellulose andsuch artificial resins as phenol-aldehyde rains, alkyd resins, styrolresins, polymerization products of vinyl chloride. vinyl acetate, ormixtures of these two, or modified resins obtained by furthercondensation, of the vinyl polymerization products with such aldehydesas formaldehyde, acetaldehyde, or furfuraldehyde. With .vinylite, whichis a mixed condensation product of 80% of vinyl chloride and 20% ofvinyl acetate, the butyl ester is compatible and forms an exceedinglytough product.

It is also compatible with such natural resins as shellac and with thelatter it forms, upon baking for a day or two at about one hundreddegrees centigrade, a very tough, resistant mass. A second convenientmethod of preparing these products involves the simple addition of analcohol, such as methyl, ethyl or butyl alcohol to the lactone and thensubjecting the mixture to vigorous refluxing. It will be appreciatedthat in this reaction several molar equivalents of the I alcohol shouldbe employed in order to provide a favorable equilibrium condition forthe reaction. The reaction may be conducted at normal or elevatedpressures as may be desired. A mineral acid such as sulfuric acid orhydrochloric acid may be added. The course of the reaction may berepresented by the following equation:

ROOC

'mon aliphatic and cyclo-aliphatic alcohols, butyl alcohol merely beingdescribed above for the purpose of illustration. In case ethyl alcoholis employed, the diethyl ester obtained has a boiling point of 204 C.under a pressure of s milli-.

. meters (absolute). The melting point is 73- 74 C. The dimethyl producthas a melting point of 83 C.

Glycollic acid esters may be prepared by reacting the sodium salt of themono ester of benzophenone 2,2 dicarboxylicacid with an ester ofchloracetic acid. For example, the sodium methyl, ethyl, propyl, butyland so forth esters, when refluxed in a suitable solvent, such as anhydrous alcohols, may be reacted with ethyl, methyl, propyl, iso-propyl,butyl or iso-butyl ester of chloracetic acid to form an ester of thegeneral type formula:

COOCHzCOOR COOR;

Example I .A nitrocellulose film may be made conveniently by forming asolution of cellulose nitrate in a solvent which may contain thefollowing ratios of ingredients:

% active solvent such as ethyl acetate, butyl acetate, etc.

20% alcohol such as denatured alcohol, butyl alcohol, etc.

55% hydrocarbon such as benzol, toluol, etc.

Thereafter there is added about 20 to per cent by weight of a simple,primary ester of benzophenone 2,2 dicarboxylic acid and the volatilesolvent removed. The dibutyl ester is a specific example of suchmaterial. However, the other esters, including the diamyl, dimethyl anddiethyl esters, may also be employed. Likewise, neutral esters, such asmethyl, ethyl and butyl benzophenone 2,2 dicarboxylic acid esters ofesterifled glycollic acid, may be employed.

Example II .A phenol aldehyde condensation product in which condensationor polymerization is only partial is dissolved in alcohol preferably toproduce a 50 per cent by weight solution. To this solution may be addeda suitable quantity (e. g. 30 per cent by weight based upon resincontent of any of the above described esters) of benzophenone 2,2dicarboxylic acid. It will be appreciated that the proportion ofplasticizer incorporated may be increased or decreased according to thedegree of flexibility desired in the product.

The use of a solvent may be dispensed with in the foregoing example byincorporating the ester in the resin while the latter is in a fluxed orfluid condition. y

Example lIL-In similar manner a resin of the 5. As a new composition ofmatter an organic.

alkyd type prepared by condensing phthalic anhydride with glycerolcontaining a small amount of glycol to obtain a soluble thermo-plasticresin may be mixed while in a molten condition with- 5 to per cent ofthe plasticizers herein named. A uniform mixture is thus obtained whichmay be employed in the manufacture of varnishes, lacquers or moldingcompositions in a manner understood by those skilled in the art.

Example I V.-A polymerized styrol resin is dissolved in a suitablesolvent such as acetone after which there is incorporated 10 to 20 percent by weight of any of the esters herein described. The solvent isthen eliminated in the usual manner.

Example V.A vinyl ester resin such, for example, as polymerized vinylacetate or polymerized vinyl chloride or a mixture of the two or theirmodified forms obtained by further condensation with such aldehydes asformaldehyde or acetaldehyde, is pulverized, after which from 2 to 20per cent of any of the foregoing plasticizers is added as a spray to thepowder. After standing for a few hours the plasticizer will have atleast partially penetrated the resin and the product may be molded inany desirable form in the usual manner.

It will be appreciated that the plasticizer may also be added to theresin while the latter is in solution or molten form is so desired.

It is understood that the invention contemplates the use of theforegoing plasticizers, not merely as separate and distinct compoundsbut in admixture with each other in various proportions. The foregoingplasticizers may also be incorporated into the resins along with suchother plasticizers as dibutyl phthalate, tricresyl phosphate, and suchsimilar materials.

These improved plasticizers, as will be noted, are colorless,non-odorous and impart a degree of flexibility and permanency to theplastic compositions not shared by any of the known organicplasticizers.

'Ihe'method of preparation of the compounds is not difiicult and theprimary materials are relatively inexpensive. For these reasons, thesecompounds are highly desirable for plasticizers from a commercialviewpoint.

Although only certain typical forms of the invention have beendescribed, it will be appreciated that numerous modifications may bemade therein without departure from the spirit, of the invention or thescope of the appended claims.

, Where the term vinyl resins appears in the claims it will beunderstood that styrol resins are included.

What I claim is:

1. A plastic material as defined in claim 6 in which the alcohol is analkyl alcohol.

2. A plastic material as defined in claim 6 in which the alcohol is abutyl alcohol.

3. As a new composition of matter an organic material selected from thecellulose esters, alkyd resins, phenolic-aldehyde resins, vinyl resinsand shellac plasticized with and containing a neutral monohydricaliphatic alcohol ester of a benzophenone dicarboxylic acid. 4. As a newcomposition of matter an organic material selected from the groupconsisting of cellulose esters, alkyd resins. phenolic-aldehyde resins,vinyl resins and shellac plasticized with and containing a neutralmonohydric alkyl alcohol ester of a benzophenone dicarboxylic acid.

a cellulose ester plasticized carboxylic acid, said ester groupconsisting of i material selected from the group consisting of celluloseesters, allwd resins, phenolic-aldehyde resins, vinyl resins and shellacplasticized with and containing a neutral butyl alcohol ester of abenzophenone dicarboxylic acid.

6. Organic plastic materials of the class con;

sisting of cellulose esters, alkyd resins, phenolicaldehyde resins,vinyl resins and shellac, admixed with a neutral monohydric aliphaticalcohol ester of benzophenone 2,2 dicarboxylic acid, said ester being aplasticizer for the materials.

7. Materials containing a plastic selected from a group consisting ofcellulose esters, phenolicaldehyde resins, alkyd resins, vinyl resinsand shellac and a neutral aliphatic alcohol ester of benzophenone 2,2dicarboxylic acid, said ester being a plasticizer for the materials.

8. The composition as defined in claim 7 and further characterized inthat the benzophenone ester contains a glycollic acidester group.

9. A plastic material as defined in claim 6 in which the alcohol ismethyl alcohol.

10. A plastic material as defined in claim 6 in which the alcohol isethyl alcohol.

11. An organic plastic composition comprising a cellulose ester admixedwith a plasticizer for said cellulose ester consisting of a neutralmonohydric aliphatic alcohol ester of a benzophenone dicarboxylic acid.

12. An organic plastic composition comprising cellulose nitrate admixedwith a plasticizer for said cellulose nitrate consisting of a neutralmonohydric aliphatic alcohol ester of a benzophenone dicarboxylic acid.

13. An organic plastic composition comprising with and containing aneutral butyl alcohol ester of'benzophenone 2,2 dicarboxylic acid.

14. Organic plastic materials of the class consisting of celluloseesters,'alkyd resins, phenolicaldehyde resins, vinyl resins and shellacadmixed with the dibutyl ester of benzophenone 2,2 dibeing a plasticizerfor the materials. a

15. Organic plastic materials of the class consisting of celluloseesters, alkyd resins, phenolicaldehyde resins, vinyl resins and shellacadmixed with the dimethyl ester of benzophenone 2,2 dicarboxylic' acid,said ester being a plasticizer for the materials.

16. Organic plastic materials of the class consisting of celluloseesters, alkyd resins, phenolicaldehyde resins, vinyl resins and shellacadmixed with the diethyl ester of benzophenone 2,2 dicarboxylic acid,said ester being a plasticizer for the materials.

17. An organic plastic composition comprising a cellulose esterplasticized the dibutyl ester of benzophenone 2,2 dicarboxylic acid.

18- An organic plastic composition comprising a cellulose esterplasticized with and containing the dimethyl ester of benzophenone, 2,2dicarboxylic acid.

19. An organic plastic composition comprising ylic acid.

COURTNEY CONOVER.

with and containing CERTIFICATE OF CORRECTION. Patent No. 2,1LL7,2LL2.February 1b., 1959a COURTNEY CONOVER.

It "is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as followszt-Page 5,,second coiumn, line 16, claim'Y, after the word "neutral" insertmonohydric; and that the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Officea Signedahd sealed this 11th day of April, A0 D..1959..

Henry Van Arsdale (Seal) Acting Commissioner of Patentsc

